Analysis of conducted EMI emissions from PWM inverter based on empirical models and comparative experiments

For the purpose of investigation of electromagnetic interference (EMI) mechanisms in a PWM inverter, empirical models and comparative experiments were studied in both time-domain and frequency domain. Models of the major circuit components including switching devices, passive components and interconnects were obtained with physics-based device modeling and time-domain reflectometry (TDR) for parasitics characterization. A full-bridge inverter was then constructed with all empirical models included to study the fundamental mechanisms by which the EMI noises are excited and propagated. With separation of common- and differential-mode EMIs, the simulation results were compared with actual experiments to examine the significant roles of parasitic elements coupled with device switching dynamics in EMI generations